Field of the Invention
The present invention relates to a projector.
Description of the Related Art
In a projector, a rod integrator is used to uniformly illuminate a spatial light modulator with light from a light source. As the light source, using an area light source such as an LED has become popular. Each of Japanese Patent Laid-Open Nos. 2006-220911 and 2004-93623 describes an apparatus including an LED and a rod integrator. In the apparatus described in Japanese Patent Laid-Open No. 2006-220911, the size of the entrance plane of the rod integrator is the same as that of the light emitting plane of the LED. In the apparatus described in Japanese Patent Laid-Open No. 2004-93623, the size of the entrance plane of the rod integrator is made larger than that of the light emitting plane of the LED to cause the entrance plane of the rod integrator to capture light from the LED as much as possible.
In the apparatus described in Japanese Patent Laid-Open No. 2006-220911, however, highly accurate alignment is necessary because the light capturing amount from the LED decreases if the LED and the rod integrator are shifted with respect to a direction perpendicular to the optical axis.
In the apparatus described in Japanese Patent Laid-Open No. 2004-93623 as well, the LED and the rod integrator need to be aligned at a high accuracy. In the apparatus described in Japanese Patent Laid-Open No. 2004-93623, the alignment accuracy is raised by, for example, holding the LED and the rod integrator using the same member. However, since the processing accuracy of the holding member needs to be high, the cost increases. In addition, when holding the LED and the rod integrator using the same member, exchanging the LED takes a long time because the rod integrator also needs to be detached when exchanging the LED.